A vibrating rod generates a water wave in a ripple tank. The graph shows the wave’s displacement at one particular moment as it moves away from the rod. The wave speed is $2.0\,\text{cm s}^{-1}$. What is the frequency of the wave?
- A$0.8\,\text{Hz}$
- B$1.6\,\text{Hz}$
- C$2.5\,\text{Hz}$
- D$5.0\,\text{Hz}$